System and method for time synchronizing nodes in an automotive network using input capture
First Claim
1. A method for time synchronizing nodes in a switch fabric of a vehicle communication network, the nodes in the switch fabric joined by communication links for the transmission of data packets there between, the method comprising the steps of:
- transmitting an initial synchronization message from a first node to a second node;
transmitting an acknowledge ready message from the second node to the first node;
transmitting a reference synchronization message from the first node to the second node;
capturing a first timestamp associated with the reference synchronization message at the first node and a second timestamp associated with the reference synchronization message at the second node;
transmitting the second timestamp from the second node to the first node;
computing an offset in the first node based on the first timestamp captured at the first node and the second timestamp transmitted from the second node; and
storing the offset in the first node for subsequent use in time synchronizing data packets transmitted by the first node to other nodes in the switch fabric.
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Accused Products
Abstract
A system and method for time synchronizing nodes in a switch fabric network of a vehicle. The network has a plurality of nodes that are joined by communication links for the transmission of data there between. Each node of the switch fabric may include a processor, a memory, a clock, a transceiver, and an input capture. The memory is adapted to store and retain timer offsets associated with communication links with neighboring nodes. The transceiver is adapted to transmit and receive synchronization messages between the node and neighboring nodes. The input capture is adapted to capture a timestamp associated with the transmission of synchronization messages. The processor is configured to compute the timer offsets associated with the communication links with neighboring nodes based on the captured timestamps by the input capture function. The computed offsets may then be broadcast and stored by the nodes for subsequent use in time synchronizing data packets through the switch fabric network.
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Citations
22 Claims
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1. A method for time synchronizing nodes in a switch fabric of a vehicle communication network, the nodes in the switch fabric joined by communication links for the transmission of data packets there between, the method comprising the steps of:
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transmitting an initial synchronization message from a first node to a second node;
transmitting an acknowledge ready message from the second node to the first node;
transmitting a reference synchronization message from the first node to the second node;
capturing a first timestamp associated with the reference synchronization message at the first node and a second timestamp associated with the reference synchronization message at the second node;
transmitting the second timestamp from the second node to the first node;
computing an offset in the first node based on the first timestamp captured at the first node and the second timestamp transmitted from the second node; and
storing the offset in the first node for subsequent use in time synchronizing data packets transmitted by the first node to other nodes in the switch fabric. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method for time synchronizing a switch fabric of a vehicle communication network, the switch fabric having at least a first node and a second node, the first node and the second node joined by a communication link for the transmission of data packets there between, the method comprising the steps of:
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initiating a synchronization dialogue between the first node and the second node;
designating the first node as the initiator of the synchronization dialogue and the second node as the receiver of the synchronization dialogue;
transmitting a synchronization message from the first node to the second node;
capturing a first timestamp associated with the reference synchronization message at the first node and a second timestamp associated with the reference synchronization message at the second node;
transmitting the second timestamp from the second node to the first node;
computing an offset in the first node based on the first timestamp captured at the first node and the second timestamp transmitted from the second node. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A vehicle network comprising:
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a plurality of nodes joined by communication links for the transmission of data there between;
each node of the vehicle network including a processor, a memory, and a clock, the memory adapted to store and retain a timer offset associated with a communication link between the node and a neighboring node;
a transceiver disposed within each node, the transceiver being adapted to transmit synchronization messages to the neighboring node in the vehicle network when the node is an initiator of a synchronization dialogue and being adapted to receive synchronization messages from the neighboring node in the vehicle network when the node is not the initiator of the synchronization dialogue; and
an input capture to capture a timestamp associated with the transmission of synchronization messages when the node is an initiator of the synchronization dialogue and a timestamp associated with the transmission of synchronization messages by the neighboring node when the node is not an initiator of the synchronization dialogue;
wherein the processor is operable to compute the timer offset based on the timestamp captured by the input capture and a neighboring timestamp received from the neighboring node. - View Dependent Claims (20, 21, 22)
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Specification